On this day, Feb. 18, in 2001, FBI agent Robert Hanssen was arrested for spying for the Soviet Union and Russia in what is possibly the worst intelligence breach in U.S. history.

Hanssen was taken into custody minutes after leaving a package of highly classified information at a “dead drop” site under a wooden footbridge at Foxstone Park in Vienna, Va.

Known for his arrogance and religious piety, Hanssen asked the agents who arrested him, “What took you so long?”

His activities have been described by the U.S. Department of Justice’ as “possibly the worst intelligence disaster in U.S. history.”

Hanssen was a counterintelligence expert and the bureau’s liaison to the State Department. It was in a key position to slip secrets to his handlers.

His spying began in 1979 by volunteering to furnish highly sensitive documents to KGB intelligence officers assigned to the Soviet embassy in Washington, D.C.

Over the next 22 years, Hanssen sold the information for $1.4 million in cash and diamonds. He shared details about spy technology and how the U.S. would react to a Soviet nuclear attack.

His private exploits were just as devious. Hanssen asked a neighbor watch him have sex with his wife in their home, without his wife’s knowledge. He later installed a closed circuit camera in his bedroom for his friend’s viewing.